New to mini forums, so please be kind. I bought a 2008 R56 with all JCW upgrades and everything was going fine... until it wasn't-- timing chain snapped. We replaced the timing kit and torx bolts, dropped the oil pan, etc. Car ran great for a month. Now, it is almost as if the timing chain has slack again. I've seen the timing chain tensioner washer mod and was wondering if this was successful? Size of the washer??? The pics look like a 1/8" washer was used but all links in other forums do not work.

 

Just to be sure: the chain tensioner was also replaced (with the newest version, i.e. part no. 11317607551)?

What is "almost" meant to mean? Please alaborate on how the engine is running and whether any codes are thrown.

I've never come across any such mod. Kindly provide any links.

That said, I would not be willing to try such a mod. There is more to a worn tensioner than just reduced spring pre-load. Nor can I imagine that BMW/MINI would go through the effort of developing a newly designed, differently sized chain tensioner (and throwing out all old stock) if the issue could have been resolved by simply using a thicker gasket ring.

If there is indeed slack or timing misalignment in a newly installed chain tensioner (kit), then I'd insist on having the chain slack measured and (if no slack) check the timing.

Either way: installation was not performed to the book, meaning everything has to come out, bolts replaced and re-installed (hopefully correctly this time).

FWIW: I just measured the thickness of the chain tensioner's (used) factory gasket ring out of my N16 engine (same part no. as in the N14): 1.55mm

OT: Note that there are differences between the engine of a factory JCW and the engine of a Cooper S with JCW upgrades.